Pinus occidentalis

Swartz 1788

Common names

Hispaniola pine; Pino criollo [Spanish].

Taxonomic notes

This species shares a sub-clade of section Australes with other species of the southeastern U.S. and Caribbean, including P. caribaea, P. cubensis, P. echinata, P. elliottii, and P. palustris. An analysis examining both nuclear and cytoplasmic DNA markers consistently placed P. occidentalis sister to P. cubensis (Gernandt et al. 2018), and a plastid haplotype analysis found 12 distinct haplotypes in P. occidentalis, of which two were shared with P. cubensis, and none shared with any other related pines. The type is from Haiti, Nippes, O.P. Swartz s.n.. Synonym P. occidentalis Sw. var. baorucoensis Silba 1985.

Description

Trees to 40 m tall and 120 cm dbh, typically with a single erect trunk, and a crown of spreading branches forming an irregular, open crown. Bark on mature trees thick, rough, scaly, breaking into irregularly square plates divided by deep fissures, gray-brown weathering to gray. Twigs uni-nodal, glaucous to pruinose in the first year, later brown. Cataphylls slender, subulate to caudate, straight or recurved, scarious, brown. Vegetative buds ovoid to ovoid-oblong, acute; terminal bud 10-15 mm long; lateral buds shorter, usually slightly resinous. Fascicle sheaths persistent, (8-)10-15 mm long, lustrous silvery brown, weathering gray-brown. Leaves in fascicles of 3-5, persisting 3 years, straight or slightly curved, more or less rigid, (11-)14-18(-20) cm long, 1.2-1.4 mm thick, acute, light green, with stomata on all faces. Pollen cones cylindrical, 15-25 × 5 mm, pinkish yellow, turning yellowish brown. Seed cones subterminal, solitary or in pairs on 1-2 cm long straight or recurved peduncles, persisting several years after seed dispersal, falling with peduncle attached. Mature cones ovoid to ovoid-conical, straight or curved, nearly symmetrical, (4-)5-9(-11) cm long. Seed scales oblong, straight or recurved, thin woody. Apophysis slightly raised, transversely keeled, rhombic to pentagonal, dark brown, striate, weathering gray. Umbo dorsal, raised and often curved, usually armed with an inflexed, 2-3 mm long spine. Seeds obliquely obovoid, flattened, 5-6 × 3-4 mm, light, mottled grey-brown. Seed wings obliquely ovate or oblong, 12-18 × 4-6 mm, reddish brown with black or grey tinge or stripes (Farjon 2010).

Distribution and Ecology

Hispaniola: Haiti and the Dominican Republic. It occurs in the Cordillera Central, the Sierra de Neiba, and the Sierra de Bahoruco in the Dominican Republic. In Haiti, it is known from the Massif du Nord, Presqu'ile du Nord-Ouest, Plaine Central, Montagnes Noires, Chaine de Matheux, Montagnes du Trou d'Eau (the western extension ofthe Sierra de Neiba), Massif de la Selle (the western extension of the Sierra de Bahoruco), Massif de la Hotte, and fie de la Gonave (Zanoni et al. 1990). Grows at (200-)900-2700(-3200) m elevation in mixed or pure stands (Farjon and Styles 1997). Occasional reports of this species elsewhere in the Caribbean reflect either introduced trees or similar species such as the closely-related P. caribaea or P. cubensis. Climate tropical, seasonal, with ca. 1200-2300 mm annual rainfall and a 3-5 month winter dry season. Soils are carbonate at lower altitudes, or more acid, clay-like and shallow in the Cordillera Central. The pines occur in a variety of vegetation types, mostly occupying shallow, nutrient-poor soils and rock outcrops, in open or dense, pure or mixed stands with various broad-leaved trees and shrubs. In grazed areas Pteridium aquilinum can dominate the ground cover; in frequently burnt areas grasses (e.g. Danthonia domingensis, Andropogon spp.) and again Pteridium replace shrubs and small trees (Farjon 2010).

Being the only species of Pinus on Hispaniola, and formerly abundant over much of the island, it has been heavily exploited for timber. By 1991 it had been depleted from an estimated 3 million hectares of primeval, more or less pure pine forests to perhaps less than 5% of that area. Protection in the Dominican Republic is limited and inadequate; in Haiti it is nonexistent (Farjon 2013). The 2013 conservation assessment, which raised the threat level to Endangered, found a decreasing population trend due largely to unregulated and unsustainable logging practices on both subsistence and large commercial scales. The estimated area of occupancy is only 164 km² within a range of 37,872 km², indicating a severely fragmented population structure (Farjon 2013).

Zone 10 (cold hardiness limit between -1°C and +4.4°C) (Bannister and Neuner 2001).

Remarkable Specimens

The oldest known tree was at least 211 years old when it died (crossdated; 1786-1997), sampled as part of an exploratory dendrochronological study on Hispaniola that determined this species, when growing at high elevation, produces interannual rings with high tree-to-tree correlation (Speer et al. 2004).

Ethnobotany

Since the onset of Euroamerican settlement, this pine has been extensively exploited for timber production, leading directly to its current endangered status (Farjon 2010, 2013). Other uses have included firewood, kindling (the resin-filled splinters are used to start cooking firewood or charcoal, being called "cuaba" in the Dominican Republic), resin for terpentine and trementine (pine oil with kerosene, used as a cleaning agent and also as a liquid fuel for hurricane lamps in the Dominican Republic), pine oil (cleaning agent), and pino-ozua (cleaning agent, a mixture of the essential oils from Pinus occidentalis and ozua, Pimenta racemosa var. ozua). Occasionally it has been used as a Christmas tree and as an ornamental tree for home gardens. Since ca. 1970, it has been used in reforestation on the island (Zanoni et al. 1990).

Observations

In Haiti, it is best seen in La Visite National Park. The highest peak, the Pic Cabaio reaches 2,300 meters. Pinus occidentalis is the dominant tree species. La Visite National Park is accessible from a footpath in Furcy, and from Marigot to Fond Jean Noël Macary where two secondary roads have recently been rehabilitated. In the Dominican Republic, it appears to be well represented in Parque Nacional Armando Bermudez.

I have a report of it in Puerto Rico, along Km.13-16 of Route 120, in Maricao Forest Reserve; if so, it is introduced (Vladimir Dinets e-mail 2000.01.04).

Remarks

The epithet means "of the west" and the type locale is, in fact, west of many places, including most of the rest of Hispaniola.

This species is the only known host for the dwarf mistletoe Arceuthobium bicarinatum, which occurs mostly on Hispaniola (Hawksworth and Wiens 1996).

Citations

Farjon, Aljos. 2010. A Handbook of the World's Conifers. Leiden, Netherlands: Brill Academic Publishers.

Farjon, Aljos. 2013. Pinus occidentalis. The IUCN Red List of Threatened Species 2013: e.T34192A2850209. https://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T34192A2850209.en. Accessed 2020.05.04.

Gernandt, D. S., X. Aguirre Dugua, A. Vázquez-Lobo, A. Willyard, A. Moreno Letelier, J. A. Pérez de la Rosa, D. Piñero, and A. Liston. 2018. Multi-locus phylogenetics, lineage sorting, and reticulation in Pinus subsection Australes. American Journal of Botany 105(4):711–725.

Speer, James H., Kenneth H. Orvis, Henri D. Grissino-Mayer, Lisa M. Kennedy, and Sally P. Horn. 2004. Assessing the dendrochronological potential of Pinus occidentalis Swartz in the Cordillera Central of the Dominican Republic. The Holocene 14(4):563-569.

Swartz, O.P. 1788. Nova genera et species plantarum seu prodromus descriptionum vegetabilium. Stockholm-Uppsala. p.103.

Zanoni, T. A., R. P. Adams, and E. J. Miller. 1990. Essential oils of plants from Hispaniola: 2. The volatile leaf oil of Pinus occidentalis (Pinaceae). Moscosoa 6:219–222.

See also

This episode of Crime Pays But Botany Doesn't features quite a bit of footage of P. occidentalis in habitat.

The species account at Threatened Conifers of the World.

Jardón-Barbolla, L., P. Delgado-Valerio, G. Geada-López, A. Vazquez-Lobo, and D. Pinero. 2010. Phylogeography of Pinus subsection Australes in the Caribbean Basin. Annals of Botany 107(2):229–241.